JUNE – LIGHT
June 21 is Summer Solstice—the longest day of sunlight north of the equator— and in recognition of the huge role the Sun plays in our lives and global history, it’s also important to look at both Daylighting and Electric Lighting.
Studies show that daylighting can provide substantial benefits to staff and employers alike, but improper usage can lead to unpleasant conditions within the structure. The benefits of daylighting will only be realized if it is implemented correctly. Improper use of daylighting can reduce productivity and increase employee absenteeism due to the possibility of extremely high lighting levels, excessive glare, and high temperatures.
During June, several of us ran around aiming light meters at things in our offices, mapping view and daylight corridors, looking at window coverings, and counting ceiling light fixtures to determine our Lighting Power Density, and working through Spatial Daylight Autonomy analysis of the results. If we didn’t already know about the automation on our lighting circuits, we’ll found out what they were programmed for and determined if they can be tweaked to be more effective. We also learned what percentage of all our offices have access to and utilize daylighting — or don’t.
• The Culver City office is well lit on the north side but darker toward the south side.
• The Las Vegas office is well lit throughout even though there are several glary areas around the perimeter.
• The Minneapolis office is well lit on the top floor but with each level down the quality of lighting declines.
• All offices offer excellent views to the outside except the south side of Culver City and the lower floors of the Minneapolis office.
• Lighting Power Density (LPD) of CGA offices are between 0.5 watts per square foot to 0.85 watts per square foot.
• All offices have some sort of automated lighting control except San Diego. Phoenix has daylight sensors but they are not connected to the tunable fixtures and therefore inactive.
• Provide task lights at all desks and encourage their use.
• Retro-commission all lighting control systems to maximize turning off and/or dimming lights.
• Where no automatic control systems exist, train staff in how to manually control lights to maximize energy savings.
• Evaluate color temperature of main space lighting in all offices. Standardize to 4000k except where tunable fixtures are in use.
• Provide adequate window/skylight coverings to prevent excessive glare at any workstation.